Plasma Decap/Depassivation for IC Failure Analysis

The Importance of Plasma Decapsulation in Today’s Semiconductor Device Industry

Semiconductor process technologies have significantly evolved as Moore’s Law predicted.  The device structures have become much more complex in order to achieve high performance, and the footprint of these devices are getting smaller so that they can be integrated into consumer electronics such as smartphones and tablets.

While the semiconductor devices are widely used in the consumer electronics, the Internet of Things (IOT) is burgeoning, especially in the field of vehicles and industrial applications. This technology connects people and environments with lots of sensors and electronics. It will create energy-efficient and smart cities. While the IOT requires a huge amount of the devices to create the broad network of the consumer products and industrial sensors, the quality and reliability of these devices is still a big challenge.

Failure Analysis (FA) is the technique to detect a failure location and a failure mode of a device by using various methods. The information on these failures is needed to be fed-back promptly in order to improve the quality and reliability of the devices in production.

Decapsulation (sometimes called as depassivation, delayering or deprocessing) is one of the key techniques in the whole FA procedures. This technique is used to remove passivation and reveal the under-layers of the devices for subsequent inspection. acid decapping and plasma decapping technologies are widely used for the decapsulation. Acid decapping using solution such as nitric acid and sulphuric acid is a useful technique for passivation removal but it sometimes causes corrosion of metal lines such as copper and aluminum wires. plasma decapping processes using dry etching technologies are slower than acid decapping processes, however the processes can remove a specific material layer and reveal under-layers and metal lines with high selectivity.